Knob for spindles of electrical apparatus and the like



2,571,681 ECTRICAL 'r LIKE 12, 1947 Oct. 16, 1951 E. w. CLARK KNOB FOR SPINDLE 0F APPARATUS AND Flled March INVENTOR.

3 P c ma M Q Patented 001.16, 1951 KNOB FOR SPINDLES OF ELECTRICAL APPARATUS AND THE LIKE Earle Wiley Clark, Grand Rapids, Mich., assignor to Keeler Brass Company, Grand Rapids, Mich., a corporation of Michigan Application March 12, 1947, Serial No. 734,178

This invention relates to improvements in knobs for spindles of electrical apparatus and the like.

The main objects of this invention are:

First, to provide a knob for the spindle of an electrical apparatus such for example as a radio control which is highly attractive in appearance, may be economically produced, and is effectively insulated although partially formed of metal.

Second, to provide a knob which may be quickly and effectively engaged with a spindle.

Objects relating to details and economies of the invention will definitely appear from the description to follow. The invention is defined in the claims.

A structure which embodies the features of the invention is clearly illustrated in the accompanying drawing, in which:

Fig. 1 is a longitudinal section of a knob embodying the invention, the section being taken on line l-l of Figs. 2 and 3.

Fig. 2 is a front elevation view.

Fig. 3 is a rear view, the knob being shown as mounted on a spindle of D section.

Fig. 4 is a longitudinal section of a modified form or embodiment of the invention adapted to be engaged with a threaded spindle.

In the embodiment of my invention illustrated in Figs. 1, 2 and 3 the body I is formed of molded plastic insulating material and comprises a base portion 2, a reduced neck portion 3 and grip portion 4. The stem 5 is formed integrally with the body, the stem illustrated being shouldered or stepped at 6 and having a longitudinal slit 1 therein providing springable stem members 8 and 9. The inner end of the body portion presents a fiat surface or shoulder Ill.

The stem is designed to enter a suitable opening in the instrument panel of a radio or the instrument panel of an automobile, airplane or the like. The neck portion is inwardly curved and flared outwardly into the grip portion. The grip portion is undercut at I l providing a rim portion I2 of reduced thickness.

The cap l3, which is formed of sheet metal, is suitably designed for ornamental purposes and is provided with an inwardly facing U-shaped peripheral portion or flange M which embraces the reduced portion of the grip, being retainingly clamped thereon with the edge l5 of the flange abutting the shoulder l6 resulting from the undercut so that the edge of the cap is guarded, protecting the operator from injury such as might result from the relatively sharp edge of the thin cap.

5 Claims. (01.74-553) The structure illustrated in Figs. 1, 2 and 3 is designed to be mounted on a stem I 1 of D section, the stem member 8 being internally curved to receive the rounded portion of the stem while the member 9 has a flat surface l8 engaging the flat side of the spindle. Where no substantial pull is likely to be exerted upon the knob the gripping engagement of the stem members is suflicient to retain the knob. Where pull is likely to be exerted upon the knob, the knob is provided with an internally threaded bore l9 adapted to receive the spindle, as is shown in Fig. l. The body has a reduced portion 20 adapted to enter an opening in the instrument or control panel. Otherwise the structure is substantially that shown in Figs. 1, 2 and 3.

The appearance of the knob may be considerably varied by changing the design of the cap. If desired the cap may be finished to correspond with the color of the body member, or it may be of contrasting color or finish, thereby providing further variations. Another advantage is that if desired suitable indicia may be stamped or embossed on the cap.

I have illustrated and described the invention in two highly practical embodiments thereof. I have not attempted to illustrate or describe other embodiments or adaptations which I contemplate as it is believed this disclosure will enable those skilled in the art to embody or adapt the invention as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A knob for a control spindle of an electrical apparatus comprising a hollow body open at its outer end, the inner wall of the body diverging generally outwardly towards the outer end, said body being of molded plastic electrical insulating material including a base portion, .a reduced neck portion and a grip portion, the neck portion being flared outwardly and merging into the grip portion, and a stem composed of insulating material and molded integrally with said base portion and projecting exteriorly of the hollow body away from the base portion, said base portion constituting means adapted to be disposed exteriorly of a panel, and said stem constituting means adapted to project into an opening in a panel and engage a spindle, the grip portion being undercut at the periphery thereof to provide a rearwardly facing annular recess and an outwardly facing shoulder at the edge of the recess, and a sheet metal cap having an inwardly facing flange to provide an inwardly facing channel for retainingly embracing the periphery of the grip portion with its inner edge lying within the undercut thereof and guarded by the shoulder at the inner edge of the undercut, said neck portion flaring concavedly outwardly and merging into said grip portion in the form of a radially outwardl extending flange-like member for engagement within the channel section of said cap, said body and stem electrically insulating a spindle received in said stem from said metal cap embracing the outer edge of said grip portion.

2. In a knob for a control spindle of an electrical apparatus, a hollow body open at its inner and outer ends, the inner wall of the body diverging generally outwardly toward the outer end, said body being of molded plastic electrical insulated material including a base portion, a reduced neck portion and a grip portion, the neck portion being flared outwardly and merging into the grip portion, and a stem composed of insulating material and molded integrally with said base portion and projecting exteriorly of the hollow body away from the base portion, the stem being longitudinally slit to provide springable spindle engaging members, one of which is curved on its inner side to receive a spindle and the other of which has a flattened inner side adapted to engage the flat side of a spindle of D section, said base portion constituting means adapted to be disposed exteriorly of a panel, and said stem constituting means adapted to project into an opening in a panel and engage a spindle.

3. A knob for control spindles comprising a hollow body open at its .outer end, the inner wall of the body diverging generally outwardly towards the outer end, said body being of molded plastic insulating material and having a stem at its inner end formed integrally therewith, the sides of the body being inwardly curved to provide a reduced neck and to provide a radially outwardly extending grip portion at the outer end of the body, the body being undercut at its outer end to provide a relatively thin peripheral edge portion, and a sheet metal cap having an annular flange clamped upon said edge portion with its inner edge lying within the undercut, said body and stem insulating a spindle received by said stem from the metal cap.

4. A knob comprising a hollow body molded of plastic insulating material, and a sheet metal cap having a flange extending inwardly from the periphery thereof to provide an inwardly opening channel, said body having inner and outer ends and being reduced between said ends to provide a neck portion, said inner end constituting a base portion, said neck portion tapering outwardly towards said outer end to provide a radially outwardly extending flange-like member constituting a grip portion of the body and constituting means havingthe peripheral edge portion embracingly retained within said channel, the outer end of said hollow body being open and closed by said cap, said base portion having means for receiving a spindle, said body insulating a spindle received in said spindle receiving means from said metal cap.

5. A knob comprising a hollow body molded of plastic insulating material, and a sheet metal cap having a flange extending inwardly from the periphery thereof to provide an inwardly opening channel, said body having an inner end constituting a base portion, an outer end and an intermediate portion tapering outwardly towards said outer end to provide a radially outwardly extending flange-like member, said flange like member providing a grip portion for the body and providing means having the peripheral edge portion thereof disposed within said channel, the

outer end of said hollow body being open and closed by said cap, said base portion having means for receiving a spindle, said body insulating a spindle received by said spindle receiving means from said metal cap.

EARLE WILEY CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Purinton Aug. 30, 1949 

